Modelling of emerging threats and epidemics
Robert Koch Colloquium, 19 May 2025
https://epiforecasts.io
What is a model?
Models are a tool to combine data (what we know) with assumptions and theory (what we think) to learn about what we don’t know.
Example: contact tracing and early COVID
January 2020: Can COVID-19 be controlled by contact tracing?
Probability of control vs. tracing effort
Probability of control depends on intensity of transmission and contact tracing effort.
What happens next?
Time series of case incidence.
Epidemiological context
Acute Respiratory Infection (ARI) consultations in Germany.
What really happened
Acute Respiratory Infection (ARI) consultations in Germany.
How wrong are models? — Forecast evaluation
Assess quality of models by how closely prediction matches reality
Types of predictive modelling
Forecasts vs. Scenarios
Image from: https://covid19scenariomodelinghub.org/
Forecast hubs support systematic collection of forecasts
Ensembles beat individual models
Case forecasts degrade quickly
Humans were better than models at predicting cases, but not deaths
No model type dominates
Broader evaluations: not just forecasts
Any model of the future is a prediction and can be evaluated as such.
Usefulness doesn’t have to coincide with accuracy
Few frameworks exist to assess utility
Collaboration with Robert Koch Institute / WHO Pandemic Hub.
Preparing for the next epidemic: predictable tasks
Figure courtesy of Adam Kucharski
Predictable task: mpox nowcasting
Unpredictable task: the impact of network structure on mpox transmission
Initiatives to create and disseminate tools for predictable tasks.
Thank you
Slides at
